Rigging character, mesh not following bones
It looks like your ears are very dense and make the parenting fail, so you should simplify them. More genarally your whole mesh is way too dense, especially ears, eyes and hands. You should avoid that, high-poly meshes make any edit and animation very tedious, and if you use a Subdivision Surface modifier it makes it even more useless. So rework your mesh before parenting.
Also you have 2 Subdivision Surface modifiers, keep one only, give it a level of 2 but disable it until you have a good mesh.
And don't forget to apply the scale of the armature and mesh.